Usefulness of Soluble Transferrin Receptor in the Diagnosis of Iron Deficiency Anemia in Rheumatoid Arthritis Patients in Clinical Practice

Table 3

Sensitivity, specificity, and predictive values of sTfR and standard parameters of iron status alone and in combination for the diagnosis of IDA or ACD/IDA () in patients with ().

	Sensitivity %	Specificity %	PPV %	NPV %
RBCI	19.0	100	100	68.7
Ferritin	76.2	78.4	66.6	85.3
Ferritin/RBCI	76.2	78.4	66.6	85.3
Ferritin/TSAT/RBCI	85.7	86.5	78.8	91.6
Ferritin/TSAT/CRP/RBCI	76.2	100	100	88.1
Ferritin/TSAT/CRP/sTfR/RBCI	57.1	100	100	80.5
sTfR	66.7	97.3	93.3	83.9

RBCI: red blood cell indices; IDA: iron deficiency anemia; ACD: anemia of chronic disease; ACD/IDA: anemia of chronic disease with concomitant true iron deficiency; TSAT: transferrin saturation; sTfR: soluble transferrin receptor.